Abstract : Enhanced Direct Memory Access (EDMA) enables background batch data transfer independently of the CPU, and is used for fast data exchange in digital signal processors (DSPs). This paper proposes a strategy for optimizing data access using EDMA in the implementation of an AVS video encoder on the TMS320DM6446 DSP platform, thereby reducing the overhead of data movement on the DSP. By rationally arranging data access, parallel operation of DMA and DSP is achieved, thus improving the algorithm's encoding rate. Data storage takes into account the chip's memory size and the rationality of the algorithm structure. Cache coherence and other issues are considered when using DMA. Experimental results show that using EDMA for data movement in the algorithm reduces the DSP's computational burden and significantly improves the encoding rate.
Keywords : EDMA, TMS320DM6446 DSP, AVS
1. Introduction The AVS video compression standard boasts high coding efficiency but also suffers from high algorithmic complexity. The encoding process inevitably involves significant data movement due to data reuse, burdening the DSP and consuming considerable time. Furthermore, the ported embedded operating system also consumes memory, necessitating the storage of video data in external memory. Improving encoding and decoding speed requires addressing the data storage issue. This paper utilizes the TMS320DM6446, TI's latest digital signal processor (DSP) designed for multimedia processing. Its Enhanced Direct Memory Access (EDMA) is crucial for DSP image processing systems, enabling data movement within mapped memory without CPU intervention, thus reducing the DSP's workload. Flexible use of EDMA can significantly improve data transfer efficiency. This paper ports and optimizes the AVS algorithm on the DM6446 hardware platform, employing EDMA3 for data access during program execution, effectively improving the algorithm's encoding rate.
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